Bayesian predictions for A =6 nuclei using eigenvector continuation emulators

We make ab initio predictions for the A =6 nuclear level scheme based on two- and three-nucleon interactions up to next-to-next-to-leading order in chiral effective field theory (χ EFT ). We utilize eigenvector continuation and Bayesian methods to quantify uncertainties stemming from the many-body method, the χ EFT truncation, and the low-energy constants of the nuclear interaction. The construction and validation of emulators is made possible via the development of JUPITERNCSM—a new M -scheme no-core shell model code that uses on-the-fly Hamiltonian matrix construction for efficient, single-node computations up to N_max=10 for ⁶Li. We find a slight underbinding of ⁶He and ⁶Li, although consistent with experimental data given our theoretical error bars. As a result of incorporating correlated χ EFT -truncation errors we find more precise predictions (smaller error bars) for separation energies: S_d(⁶Li) =0.89 ±0.44 MeV , S_{2 n}(⁶He) =0.20 ±0.60 MeV , and for the beta decay Q value: Q_β⁻(⁶He) =3.71 ±0.65 MeV . We conclude that our error bars can potentially be reduced further by extending the model space used by JUPITERNCSM.